Recently, along a trend of energy saving, a demand for illumination or a backlight that uses an LED is increasing. The LED that is used is a white light-emitting LED in which a phosphor is disposed on an LED chip that emits light of a wavelength of blue or near ultraviolet.
As this type of white light-emitting LED, recently, an LED, which uses a red light-emitting nitride phosphor and a green light-emitting phosphor in which blue light from a blue LED chip is set as excitation light on the blue LED chip, has been used. Particularly, as the red light-emitting nitride phosphor, a phosphor (hereinafter, may be referred to as “SCASN phosphor”), in which an augmenting agent is added to a parent body expressed as (Sr, Ca)AlSiN3, and the like has been developed (PTL 1 and PTL 2).
To improve luminescent properties of the nitride phosphors, for example, PTL 3 discloses a method in which the amount of Cu is set to a constant value or less. In addition, for example, PTL 4 discloses a method in which the amount of sulfur or phosphorous is set to a constant value or less, and the like so as to control the amount to a specific composition region.